I have been getting about 15 MPG with a 4.10 gear and285/75/16 tires. Mixed driving to and from work a little country a little X-way and very little city. I am wondering if milage is about the same for others. I am also alittle confused by a statement I saw on a thread that stated a 3.55 with 305 tires would get better milage with 4.10 gears ??? as far as I know 4.10 will turn higher rpms and use more fuel. but will give better takeoff and more torque for better towing. whats wrong with my thinking on this one

 

I might have been the one that made that statement, and I might have been in error.

The way I understand it:
(mpg figures are just for example)

3.55 with stock 265's gets 20mpg.
Same 3.55 with 315's gets 15mpg.

4.10 with stock 265's gets 15mpg
4.10 with 315's gets 20mpg.

Taller tire on the 4.10 puts the ratio closer to the 3.55, which nets better fuel mileage.

3.55 = fuel mileage
4.10 = towing power

Oh, I'm getting 14 avg with 315's and 3.55 rear.


phox

 

Phox I think you are on the right track as I understand it the effect of putting on a taller tire is as if you lower the ratio. the tire being the final element in the gear train. but it brings up another question as to weather you are deafeating the purpose of the 4.10s by putting on the taller tire I think the final drive as stated is with the stock tires. if that is the case then by putting 285s on where 245s are stock then is the final drive ration something like 3.93 or ??? ??? ??? I guess it doesn't matter as I like ;D my set up and would not change new tires to gain a little milage. but anyhow it makes you think a bit. :-

 

I used to get 14-16 MPG with 4:10 6-speed and 285/75R16 since I installed a Edge EZ I now get 17-19 MPG.

 

I wish I knew then what I know now.
Mostly learned from this here board.

I would have gotten 4.10, and probably a 6 speed HO as well.

Guess I'll just have to add fuel to make up for the low ratio of my 3.55 and 315's (soon to be 37's ;D)


phox

 

I have a stock truck running with 3.55 and 265s. I'm only getting 15mpg at best. Last winter I was lucky to get 12mpg.

Is something wrong?

 

[quote author=doomgaze link=board=5;threadid=21807;start=0#msg204241 date=1067652198]
I have a stock truck running with 3.55 and 265s. I'm only getting 15mpg at best. Last winter I was lucky to get 12mpg.

Is something wrong?
[/quote]

I have a stock HO 2500 with 3.55 and 265 tires. I get just a little less than 17 in my normal driving, which is a 4 mile commute to work mixed in with slightly longer trips on weekends. I don't know if two extra tires makes that much difference or not.

 

I have a '97 2500 4x4 5 speed. It is stock with stock size tires, 245's and I get 19.5-22. The 19.5 is towing a 5x8 enclosed trailer and the 22 is completlt empty. These numbers are 95% freeway driving.

 

trying to understand this. i have 4.10 gears w/6 speed and 275 tires. if i go up to 315's my fuel mph will improve? i will be due for tires in about another15k miles and would like better fuel economy.

thanks,
david h

 

Going up in tire sizes does make your effective gear ratio higher, but you'll pretty much lose that effect to greater rolling resistance at lower speeds and to greater air resistance at higher speeds. So in short, I wouldn't expect a tire change to help get better fuel mileage.

 

I am currently running a 2001 HO w/6 speed and 355 gears. I replaced the 265 tires that were on the truck with 285's. I am getting around 18 MPG, although I can notice a decrease in the power/torque. Especially on hills. I normally drive between 60 - 65 MPH and can see an increase in the RPM,s compare to the smaller tires. :-
Maybe if I install the EDGE EZ it will make up for the difference!